In commercial packaging art, individual articles as well as bundles of articles, including bundles of articles on pallets, are frequently packaged using so called stretch cling film in a stretch wrapping technique. In the stretch wrapping technique, a thin web of film is stretched and applied under tension around the articles to be wrapped or bundled pater wrapping is complete, the film attempts to relax and thus applies a compressive force on the bundled articles prohibiting movement. It is desired that the stretch film have some inherent cling such that it will adhere to itself, and prevent relaxation back to its unstretched state so that the film will not unwrap and cause slippage of the stretched overlaid film layers.
As stated above, stretch wrap films are typically used in wrapping palleted loads of boxes, as well as individual boxes or articles such as furniture and the like. The stretch wrap films of the present invention may be applied various techniques such as by hand or may be applied using a mechanical apparatus specially designed to wrap pallets, for example. In one procedure for using stretch wrap films of the present invention, the load to be wrapped is to be placed upon a platform, or turntable, which is made to rotate and in so doing, to take up stretch wrap film supplied from a continuous roll. Rotational speeds are typically 5 to 50 revolutions per minute. Regardless of the specific wrapping procedure used, at the completion of the wrapping, the stretch wrap film is cut and attached to the underlying layer by cling, tack sealing, adhesive tape, spray adhesives, and the like. When the stretch film of the present invention is applied by hand, the operator typically holds an applicator or wrapping tool that holds the stretch wrap film roll. After the operator completes wrapping, the stretch wrap film is cut.
Mechanical properties that are important in stretch films include, for example, how far the film can be stretched (i.e., stretchability), the film's resistance to stretching, film tensile strength, film puncture resistance, film tear resistance and cling force.